Photovoltaic module

Abstract

The invention relates to the photovoltaic field, and provides a photovoltaic module, which comprises a battery piece, a conductor and a conductive backboard, and is characterized in that the battery piece comprises a battery body and an electrode arranged on the battery body; the conductive backboard comprises an insulating layer, a conductive layer and a back adhesive film which are stacked in sequence, wherein the insulating layer is provided with a plurality of through holes penetrating through the insulating layer; the conductor is arranged in the through hole, the electrode on the battery body is electrically connected with the conducting layer through the conductor, in the longitudinal section of the conductor, the length of the first side, in contact with the electrode, of the conductor is D1, the length of the second side, in contact with the conducting layer, of the conductor is D2, and the first side and the second side are arranged on the two opposite sides of the conductor; the length of a third side located at the narrowest position between the first side and the second side in the longitudinal section is D3, and D1gt; d3 and / or D2gt; and D3. The conductor not only can ensure the current collection and transmission efficiency, but also can save the cost.

Description

Technical Field

[0001] The present application relates to the photovoltaic field, and in particular, to a photovoltaic module with a conductive backplane. Background Art

[0002] Back contact (BC) cells, or BC cells, place the PN junction and electrodes on the back of the cell, so that there is no electrode blocking the front, increasing the area of ​​the cell that absorbs sunlight, thereby improving the cell's photoelectric conversion efficiency.

[0003] At present, BC photovoltaic modules are usually made using welding ribbon connection technology or conductive backplane connection technology. The welding ribbon connection technology requires pulling the welding wire during the welding process, so there will be stress release after the welding is completed, which will cause the battery string to bend and affect the production yield of the photovoltaic module. Compared with the welding ribbon, the conductive backplane connection has the advantages of high power and high conversion efficiency. However, the existing conductive backplane connection still has problems such as high cost and high process precision requirements. Summary of the invention

[0004] In view of this, the present application provides a photovoltaic module, in which the structural morphology of the conductor is designed to reduce the cost and the requirements for the manufacturing process.

[0005] Specifically, according to the first aspect of the present application, a photovoltaic module is provided, which includes a battery cell, a conductor and a conductive backplane, the battery cell includes a battery body and an electrode arranged on the battery body; the conductive backplane includes an insulating layer, a conductive layer and a back adhesive film stacked in sequence, wherein the insulating layer has a plurality of through holes penetrating the insulating layer; the conductor is arranged in the through hole, the electrode on the battery body and the conductive layer are electrically interconnected through the conductor, in the longitudinal section of the conductor, the length of the first side of the conductor in contact with the electrode is D1, the length of the second side of the conductor in contact with the conductive layer is D2, the first side and the second side are arranged on opposite sides of the conductor, and the length of the third side located at the narrowest point between the first side and the second side in the longitudinal section is D3, and: D1>D3, and / or D2>D3.

[0006] In some embodiments, the ratio of the length D1 of the first side to the length D2 of the second side is 1≥D1 / D2≥1 / 2.

[0007] In some embodiments, the ratio of the length D3 of the third side to the length D1 of the first side is 4 / 5≥D3 / D1≥1 / 2.

[0008] In some embodiments, the ratio of the length D3 of the third side to the length D2 of the second side is 7 / 10≥D3 / D2≥1 / 3.

[0009] In some embodiments, the length of the first side is D1, satisfying: 0.6mm≤D1≤1mm; and / or the length of the second side is D2, satisfying: 0.7mm≤D2≤1.1mm; and / or the length of the third side is D3, satisfying: 0.5mm≤D3≤0.9mm.

[0010] In some embodiments, in the cross section of the conductor, the area of ​​the first cross section through the first side is S1, the area of ​​the second cross section through the second side is S2, and the area of ​​the third cross section through the third side is S3, S1>S3 and / or S2>S3.

[0011] In some embodiments, a ratio of an area S1 of the first cross section to an area S2 of the second cross section is 1 ≥ S1 / S2 ≥ 1 / 2.

[0012] In some embodiments, the ratio of the area S3 of the third cross-section to the area S1 of the first cross-section is 4 / 5 ≥ S3 / S1 ≥ 1 / 2.

[0013] In some embodiments, the ratio of the area S3 of the third cross-section to the area S2 of the second cross-section is 9 / 10≥S3 / S2≥1 / 3.

[0014] According to a second aspect of the present application, another photovoltaic module is provided, which includes a battery cell, a conductor and a conductive backplane, the battery cell includes a battery body and an electrode arranged on the battery body; the conductive backplane includes an insulating layer, a conductive layer and a back adhesive film stacked in sequence, wherein the insulating layer has a plurality of through holes penetrating the insulating layer; the conductor is arranged in the through hole, the electrode on the battery body and the conductive layer are electrically interconnected through the conductor, in the cross section of the conductor, the area of ​​the first cross section where the conductor contacts the electrode is S1, the area of ​​the second cross section where the conductor contacts the conductive layer is S2, the first cross section and the second cross section are arranged on opposite sides of the conductor, and the area of ​​the third cross section between the first cross section and the second cross section corresponding to the narrowest part in the longitudinal section of the conductor is S3, S1>S3 and / or S2>S3.

[0015] In some embodiments, the ratio of the area S1 of the first cross section to the area S2 of the second cross section is 1≥S1 / S2≥4 / 5.

[0016] In some embodiments, a ratio of the area S3 of the third cross section to the area S1 of the first cross section is 4 / 5 ≥ S3 / S1 ≥ 2 / 3.

[0017] In some embodiments, a ratio of the area S3 of the third cross-section to the area S2 of the second cross-section is 9 / 10 ≥ S3 / S2 ≥ 2 / 3.

[0018] In some embodiments, the area of ​​the first cross section is S1, satisfying: 0.36mm²≤S1≤1mm²; and / or the area of ​​the second cross section is S2, satisfying: 0.49mm²≤S2≤1.21mm²; and / or the area of ​​the third cross section is S3, satisfying: 0.25mm²≤S3≤0.81mm².

[0019] Optionally, the electrode is a combination of one or more of a main grid line, a thin grid line, or a grid line with thickened segments.

[0020] Optionally, the electrode is a PAD point.

[0021] Optionally, in the longitudinal section of the conductor, the length of the first side of the conductor in contact with the PAD point is D1', the width of the PAD point in the direction of the first side is D, and 3 / 4≤D1' / D≤1.

[0022] Optionally, in the longitudinal section of the conductor, the length of the second side of the conductor in contact with the conductive layer is D2, |D1'-D2| / D<0.1.

[0023] Optionally, at the point of contact with the PAD, the area of ​​the first cross section of the conductor is S1', and at the point of contact with the conductor, the area of ​​the cross section of the PAD is S, 3 / 4≤S1' / S≤1.

[0024] Optional, |S1'-S2| / S < 0.1.

[0025] Optionally, the thickness of the intermetallic compound layer at the interface between the conductor and the electrode is 0.5-3 μm, and / or the thickness of the intermetallic compound layer at the interface between the conductor and the conductive layer is 0.5-3 μm.

[0026] Optionally, in the longitudinal section of the conductor, the base angle is 30°-85°.

[0027] Optionally, in the longitudinal section of the conductor, the base angle is 60°-70°.

[0028] Optionally, the conductor is a column-like structure.

[0029] Optionally, the column-like structure includes: a cylindrical-like structure and / or an elliptical-column-like structure.

[0030] Optionally, the electrode is a PAD point, and the PAD point is electrically interconnected with the conductive layer through a conductor, wherein the orthographic projection shape of the PAD point on the battery body is a circle, a chamfered square, or a chamfered rectangle.

[0031] Optionally, the battery sheet has a first PAD point and a second PAD point, wherein an area of ​​an orthographic projection of the first PAD point on the battery body is larger than an area of ​​an orthographic projection of the second PAD point on the battery body.

[0032] Optionally, the number of conductors in point contact with the first PAD is greater than the number of conductors in point contact with the second PAD.

[0033] Optionally, the material of the conductor is an alloy containing tin and bismuth.

[0034] The positive effects of this application are: The conductor of the present application has an enhanced ability to collect current on the electrode. At the same time, the current transmission capacity between the conductor and the conductive layer is also significantly enhanced, which improves the current collection and transmission efficiency while greatly reducing the amount of conductor used and saving costs. In addition, such a design allows for gaps to exist in the through-holes after the conductors are filled into the through-holes. In this way, during the preparation of photovoltaic modules, even if there are errors introduced by the process such as cell layout offset, electrode printing offset, conductor offset, insulating layer offset, and offset of the insulating layer through-holes due to heat shrinkage or punching, resulting in mismatched positions of the electrodes and insulating layer through-holes, it will not cause the conductors in the through-holes to be unable to connect and conduct electricity. Therefore, the conductor structure designed in this way can not only ensure the effective transmission of current, but also has a certain fault tolerance for the preparation process, and therefore can also correspondingly improve the yield of photovoltaic modules. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of the various embodiments of the present disclosure. It includes various specific details to assist in understanding, but these details are to be considered exemplary only. Therefore, it will be appreciated by those of ordinary skill in the art that various changes and modifications may be made to the various embodiments described herein without departing from the scope and spirit of the present disclosure. In addition, descriptions of well-known functions and structures may be omitted for clarity and conciseness.

[0036] Figure 1 A schematic structural diagram of a photovoltaic module according to some embodiments of the present application is shown.

[0037] Figure 2 A schematic diagram of a conductive backplane according to some embodiments of the present application is shown.

[0038] Figure 3 Shown along Figure 2 A schematic cross-sectional view of the dotted line 10 in FIG.

[0039] Figure 4 A schematic structural diagram showing a longitudinal section of an electrical conductor in a photovoltaic module according to some embodiments of the present application is shown.

[0040] Figure 5 A pictorial diagram showing a longitudinal section of an electrical conductor in a photovoltaic module according to some embodiments of the present application.

[0041] Figure 6 A partial schematic diagram of a battery cell in which the electrodes are PAD points according to some embodiments of the present application is shown.

[0042] Figure 7 A schematic structural diagram of a battery cell according to some embodiments of the present application is shown.

[0043] Among them, 100 represents the photovoltaic module, 1 represents the conductive backplane, 2 represents the battery cell, 11 represents the insulating layer, 12 represents the conductive layer, 13 represents the back film, 14 represents the through hole, 15 represents the conductor, 16 represents the insulating glue, 17 represents the front film, 18 represents the cover plate, 19 represents the packaging backplane, 20 represents the insulating tape, 21 represents the electrode, 22 represents the battery body, 211 represents the grid line, 212 represents the PAD point on the battery body, 151 represents the first side in the longitudinal section of the conductor, 152 represents the second side in the longitudinal section of the conductor, 153 represents the third side in the longitudinal section of the conductor, and 154 represents the bottom angle in the longitudinal section of the conductor. DETAILED DESCRIPTION

[0044] The embodiments of the present application will be described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and should not be construed as limitations on the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present application.

[0045] The features of the terms "first" and "second" in this application may include one or more features, either explicitly or implicitly. In the description of this application, unless otherwise specified, the meaning of "plurality" is two or more. In addition, "and / or" in this application means at least one of the connected objects, and the character " / " generally indicates that the objects associated with each other are in an "or" relationship.

[0046] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0047] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0048] Figure 1 FIG. 1 shows a schematic structural diagram of a photovoltaic assembly 100 according to some embodiments of the present application. Figure 1 It can be seen that the photovoltaic module 100 includes a cover plate 18, a front adhesive film 17, a battery cell 2, a conductor 15 and a conductive back plate 1 which are stacked in sequence. The materials of the cover plate 18 and the front adhesive film 17 are not further limited in this application, and those skilled in the art can select them as needed. For example, the cover plate 18 is usually transparent, and it can be a transparent polymer film, such as ETFE film, or transparent glass, such as ultra-white photovoltaic glass. The material of the front adhesive film 17 can be selected from ethylene-octene copolymer (POE), ethylene-vinyl acetate copolymer (EVA), etc.

[0049] The conductive backplane 1 includes an insulating layer 11, a conductive layer 12 and a back adhesive film 13 stacked in sequence, wherein the insulating layer 11 has a plurality of through holes 14 penetrating the insulating layer 11; the conductor 15 is arranged in the through hole 14, and the electrode 21 on the battery body 22 is electrically interconnected with the conductive layer 12 through the conductor 15.

[0050] Since the present application adopts a conductive backplane 1, it can be adapted to a battery cell 2 with a higher front power generation efficiency, such as a back contact (BC) battery cell 2. The back contact battery cell 2 includes: a traditional IBC battery cell 2 (interdigitated back contact battery), a TBC battery cell 2 (TOPCon back contact battery), an HBC battery cell 2 (heterojunction back contact battery) or a hybrid back contact battery cell 2 (i.e., the PN passivation therein is a different passivation material, for example, it can be a combination of polycrystalline silicon passivation and amorphous / microcrystalline passivation).

[0051] refer to Figure 7 In the back contact cell 2, the cell body 22 includes at least a substrate and a doping layer on the substrate, wherein the substrate is rectangular or square with a side length between 182-240 mm, and optionally can be (182±2)×(191±2) mm², (182±2)×(210±2) mm², (210±2)×(210±2) mm².

[0052] For the IBC cell 2 (interdigitated back contact cell), the cell body 22 includes a first doped semiconductor portion and a second doped semiconductor portion arranged alternately and spaced along a first direction on the substrate to form an interdigitated doped portion structure. One of the first doped semiconductor portion and the second doped semiconductor portion is n-type doped, and the other is p-type doped, and the first doped semiconductor portion and the second doped semiconductor portion are respectively provided with spaced electrode 21 structures.

[0053] For the TBC cell 2 (TOPCon back contact cell), its cell body 22 includes a tunneling oxide layer disposed on a substrate, and a first doped semiconductor portion and a second doped semiconductor portion formed by a doped polysilicon layer. The TOPCon structure formed by the stacked tunneling oxide layer and the doped polysilicon layer can provide a higher carrier lifetime and lower surface recombination for the TBC cell 2 than the IBC cell 2, which is beneficial to improving the photoelectric conversion efficiency of the TBC cell 2.

[0054] For the HBC cell 2 (heterojunction back contact cell), its cell body 22 includes an n-type doping layer and a p-type doping layer stacked on a substrate to form a heterojunction structure. Among them, the n-type doping layer includes but is not limited to microcrystalline silicon or amorphous silicon (to provide electrons), and the p-type doping layer can also use microcrystalline silicon or amorphous silicon (such as using boron as a dopant to provide holes). The HBC cell 2 helps to improve the carrier lifetime and reduce surface recombination. Furthermore, a conductive oxide layer (i.e., TCO) can be set between the surface of the n-type doping layer and the p-type doping layer and the electrode 21, which is beneficial to collect carriers in the doping area and can also play a certain anti-reflection role.

[0055] For the hybrid back contact cell 2, its cell body 22 can adopt a layer structure similar to that of the IBC cell 2 or the TBC cell 2, and configure a corresponding passivation layer structure thereon, such as a combination of at least two of polycrystalline silicon passivation, amorphous silicon passivation and microcrystalline silicon passivation.

[0056] Any of the above-mentioned back-contact cells 2 can be used as the cell 2 in the photovoltaic module 100 of the present application.

[0057] One or more conductors 15 may be disposed in one through hole 14 . Figure 1 The example shows a case where 3-4 conductors 15 are arranged in the through hole 14. When multiple conductors 15 are arranged in the same through hole 14, the number of through holes 14 on the insulating layer 11 can be reduced. Similarly, the through hole 14 needs to accommodate multiple conductors 15, and the volume of the through hole 14 is also larger. In the process of preparing the photovoltaic module 100, the through hole 14 needs to be aligned with the electrode 21 on the cell 2. A larger through hole 14 is easier to align with the electrode 21 on the cell 2, and the precision requirements for the process are lower, and the reliability of the prepared photovoltaic module 100 is better.

[0058] The different doping regions on the backlight surface of the back contact cell 2 are alternately distributed in sequence, and accordingly, the electrodes 21 arranged on the different doping regions are also alternately distributed and have different conductivity types. The conductive backplane 1 is connected to the electrodes 21 of the same polarity, and also needs to cross the electrodes 21 of different polarities. Since multiple electrodes 21 are arranged in a single through hole 14, the opposite polarity electrode 21 adjacent to a certain conductor 15 can be insulated by the insulating glue 16 on the cell 2, thereby improving the insulation effect.

[0059] Figure 2 A schematic diagram of a conductive backplane 1 according to some embodiments of the present application is shown. The side of the conductive backplane 1 close to the battery cell 2 is an insulating layer 11. For the insulating layer 11, those skilled in the art can select it as needed, and the present application does not further limit it. In some embodiments, the insulating layer 11 can be a foamed polyethylene (EPE) film. A through hole 14 is provided on the insulating layer 11, and the through hole 14 corresponds to the electrode 21 on the battery cell 2. The electrode 21 includes: a positive electrode 21 and a negative electrode 21. The insulating layer 11 can be transparent or translucent. Through the insulating layer 11, the conductive layer 12 below can be seen. The conductive layer 12 can be selected from any combination of one or more of copper, aluminum, copper-aluminum alloy, and aluminum-nickel alloy. The conductive layer 12 has an insulating tape 20, which is used to isolate the positive and negative electrodes 21. The insulating tape 20 can be a hollow area on the conductive layer 12. The conductive layer 12 can be processed by laser etching, mechanical stamping, knife removal, chemical corrosion, etc., so as to form the insulating tape 20.

[0060] Figure 3 Shown along Figure 2 The cross-sectional schematic diagram of the dotted line 10 in FIG. The through holes 14 are arranged on the insulating layer 11 at intervals. The conductive layer 12 is arranged below the insulating layer 11, and the through holes 14 on the insulating layer 11 and the conductive layer 12 together enclose a space for accommodating the conductor 15. The back adhesive film 13 is arranged below the conductive layer 12. In some embodiments, the material of the back adhesive film 13 can be selected from one or a combination of two of ethylene-octene copolymer (POE) and ethylene-vinyl acetate copolymer (EVA). In some embodiments, the conductive backplane 1 can also include an encapsulation backplane 19. The present application does not limit the material of the encapsulation backplane 19. The encapsulation backplane 19 can be glass or an organic polymer film, etc.

[0061] Continue to refer Figure 1The battery cell 2 is arranged on a side of the insulating layer 11 away from the conductive layer 12. The battery cell 2 includes a battery body 22 and an electrode 21 arranged on the battery body 22. The electrode 21 on the battery body 22 is electrically connected to the conductive layer 12 through a conductor 15. The conductor 15 can be formed by curing a conductive paste, and the conductive paste can be solder paste or conductive glue. Conductive paste is pre-set on the electrode 21 of the cell 2 or the corresponding position of the conductive layer 12 by printing, dispensing, etc. to improve production efficiency; it can also be set on the electrode 21 of the cell 2 or the corresponding position of the conductive layer 12 by printing, dispensing, etc. during the assembly manufacturing process, such as after the cell 2, the insulating layer 11, the conductive layer 12, and the back adhesive film 13 are laid out and before they are stacked, so as to reduce the process errors such as the layout deviation of the cell 2, the printing deviation of the electrode 21, the deviation of the insulating layer 11, and the deviation of the through hole 14 in the insulating layer 11 due to heat shrinkage or punching, which may cause the alignment deviation of the electrode 21 and the through hole 14 in the insulating layer 11; the conductor 15 is formed between the cell 2 and the conductive layer 12 by heating or infrared curing, so as to realize the electrical connection between the electrode 21 of the cell 2 and the conductive layer 12. The material of the conductor 15 can be selected from alloys containing tin and bismuth, such as tin-bismuth alloy, tin-lead-bismuth alloy, tin-bismuth-copper alloy, and tin-bismuth-silver alloy.

[0062] In some embodiments, the electrode 21 can be a combination of one or more of the main grid line, the thin grid line, the thickened grid line segment, and the PAD point. Among them, the "main grid line" can also be called the main grid (i.e., Busbar), the busbar electrode or the busbar grid line, which is used to collect the current of the thin grid line; the "fine grid line" can also be called the fine grid, the collector grid line, the collector electrode, the auxiliary grid, etc. The fine grid line includes the positive fine grid line and the negative fine grid line, which are respectively used to collect the majority carriers or minority carriers of different doping regions; the "thickened grid line segment" refers to the portion on the grid line used for electrical connection, and its width is greater than the width of other parts of the grid line; the PAD point can also be called a pad. The material of the electrode 21 can be a metal with relatively high electrical conductivity, such as silver, silver alloy, etc., to improve the current collection and transmission capacity of the battery cell 2. It can also be a relatively cheap metal, such as copper, copper alloy, aluminum, aluminum alloy, etc., to reduce the cost of the photovoltaic module 100. The specific material and composition ratio are not limited.

[0063] Figure 4 1 is a schematic structural diagram of a longitudinal section of a conductor 15 in a photovoltaic module 100 according to some embodiments of the present application, Figure 5 A pictorial diagram showing a longitudinal section of an electrical conductor 15 in a photovoltaic module 100 according to some embodiments of the present application.

[0064] As understood by those skilled in the art, a longitudinal section refers to the surface presented after cutting an object along the direction of the axis of the object. In the present application, the joint surface of the conductor 15 and the electrode 21 has a first center point, the joint surface of the conductor 15 and the conductive layer 12 has a second center point, and the axis of the conductor 15 refers to the line connecting the first center point and the second center point. The conductor 15 is a conductor, and when the photovoltaic module 100 generates electricity, the direction of the current usually flows along the axis of the conductor 15.

[0065] refer to Figure 4 The conductor 15 is arranged between the electrode 21 of the battery cell 2 and the conductive layer 12 for electrical interconnection. In the longitudinal section of the conductor 15, the length of the first side 151 of the conductor 15 in contact with the electrode 21 of the battery cell 2 is D1, and the length of the second side 152 of the conductor 15 in contact with the conductive layer 12 is D2. The first side 151 and the second side 152 are arranged on opposite sides of the conductor 15, and the length of the third side 153 located at the narrowest point between the first side 151 and the second side 152 is D3.

[0066] The larger D1 is, on the one hand, the longer the length of the first side 151 of the conductor 15 in contact with the electrode 21 is, the smaller the contact resistance between the conductor 15 and the electrode 21 is, and the stronger the ability of the conductor 15 to collect the current on the electrode 21 is, thereby increasing the power of the photovoltaic module 100. On the other hand, the longer the length of the first side 151 of the conductor 15 in contact with the electrode 21 is, the greater the welding pull-out force between the conductor 15 and the electrode 21 is, which effectively prevents the photovoltaic module 100 from falling off or breaking due to external factors such as wind pressure and hail during use. The smaller D3 is, the smaller the length of the third side 153 at the narrowest point between the first side 151 and the second side 152 in the longitudinal section is, that is, the middle part of the conductor 15 is thinner, which can effectively reduce the amount of conductive paste such as solder paste or conductive glue, saving costs. In addition, such a design makes it possible for a gap to exist in the through hole 14 after the conductor 15 is filled into the through hole 14. In this way, in the process of preparing the photovoltaic module 100, even if there are errors introduced by the process such as the layout deviation of the battery cell 2, the printing deviation of the electrode 21, the deviation of the conductor 15, the deviation of the insulating layer 11, and the deviation of the through hole 14 in the insulating layer 11 due to heat shrinkage or punching, resulting in the position mismatch between the electrode 21 and the through hole 14 in the insulating layer 11, it will not cause the conductor 15 in the through hole 14 to be unable to connect and conduct electricity. Therefore, the conductor 15 structure designed in this way can not only reduce the amount of the conductor 15, thereby reducing the cost, but also has a certain fault tolerance for the preparation process, so it can also correspondingly improve the yield of the photovoltaic module 100. In this application, D1>D3, the conductor 15 has a strong ability to collect the current on the electrode 21, improves the power of the photovoltaic module 100, the welding pull-out force between the conductor 15 and the electrode 21 is large, and the reliability of the photovoltaic module 100 is high. Reduce the difficulty of the process, save the amount of conductive paste, and reduce costs.

[0067] The larger D2 is, on the one hand, the longer the length of the second side 152 of the conductor 15 in contact with the conductive layer 12, the smaller the contact resistance between the conductor 15 and the conductive layer 12, and the higher the current transmission efficiency, thereby increasing the power of the photovoltaic module 100. On the other hand, the longer the length of the second side 152 of the conductor 15 in contact with the conductive layer 12, the greater the welding pull-out force between the conductor 15 and the conductive layer 12, which effectively prevents the photovoltaic module 100 from falling off or breaking at the weld due to external factors such as wind pressure and hail during use. In the present application, D2>D3, the current transmission capacity between the conductor 15 and the conductive layer 12 is strong, the power of the photovoltaic module 100 is improved, the welding pull-out force between the conductor 15 and the conductive layer 12 is large, and the reliability of the photovoltaic module 100 is high. At the same time, the process difficulty is reduced, the amount of conductive paste used is saved, and the cost is reduced.

[0068] The current collection and transmission efficiency of the conductor 15 depends on the contact resistance between the conductor 15 and the electrode 21 on the battery cell 2, the contact resistance between the conductor 15 and the conductive layer 12, and the body resistance of the conductor 15, wherein the contact resistance has a greater influence on the current collection and transmission capability than the body resistance. When D1>D3 and D2>D3, the current collection capability of the conductor 15 on the electrode 21 is enhanced. At the same time, the current transmission capability between the conductor 15 and the conductive layer 12 is also significantly enhanced. Reducing D3 has little effect on the current collection and transmission efficiency of the conductor 15. While ensuring the current collection and transmission efficiency, the amount of conductive paste such as solder paste or conductive glue is greatly reduced, thereby saving costs. In addition, such a design makes it possible for a gap to exist in the through hole 14 after the conductor 15 is filled into the through hole 14. In this way, during the preparation of the photovoltaic module 100, even if there are errors introduced by the process such as the layout deviation of the battery cell 2, the printing deviation of the electrode 21, the deviation of the conductor 15, the deviation of the insulating layer 11, the deviation of the through hole 14 in the insulating layer 11 due to heat shrinkage or punching, etc., resulting in the position mismatch between the electrode 21 and the through hole 14 in the insulating layer 11, thereby causing the through hole 14 in the insulating layer 11 to be offset, it will not cause the conductor 15 in the through hole 14 to be unable to connect and conduct electricity. Therefore, the conductor 15 structure designed in this way can not only ensure the effective collection and transmission of current and reduce costs, but also has a certain fault tolerance for the preparation process, thereby improving the yield of the photovoltaic module 100.

[0069] In some embodiments, the ratio of the length D1 of the first side 151 to the length D2 of the second side 152 is 1>D1 / D2≥1 / 2. The electrode 21 on the cell 2 has the functions of current collection and transmission, and generally uses metal silver, using the high conductivity of silver to improve the current collection and transmission capabilities of the cell 2. Since the metal used is relatively expensive and the amount used is small, the electrode 21 on the cell 2 is generally small in area. The conductive layer 12 is used in a large amount because it needs to cover the entire conductive backplane 1 of the photovoltaic module 100. Generally, relatively cheap copper foil, aluminum foil, or copper-aluminum composite foil is used, and its conductivity is not as good as that of metal silver. The conductor 15 is designed so that the ratio of the length D1 of its first side 151 to the length D2 of the second side 152 satisfies 1>D1 / D2≥1 / 2. The contact resistance between the conductor 15 and the conductive layer 12 is reduced, so that the contact resistance between the conductor 15 and the conductive layer 12 and the contact resistance between the conductor 15 and the electrode 21 reach substantially the same level, thereby improving the current transmission efficiency of the conductor 15. In addition, the welding pull-out force of the conductor 15 shows a certain variation rule along with the ratio of D1 / D2 . The test results of the welding pull-out force are shown in Table 1.

[0070] Table 1

[0071] It can be seen from Table 1 above that as the ratio of D1 to D2 of the conductor 15 decreases, the welding pull-out force increases first and then decreases. When the ratio of D1 to D2 is 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:1.6, and 1:1.7, the conductor 15 has a higher welding pull-out force.

[0072] In some embodiments, the electrode 21 and the conductive layer 12 are made of materials with the same conductive properties, or the same conductive material, such as copper, D1 / D2=1. Based on the above-mentioned size design, the welding tension between the conductor 15 and the electrode 21 tends to be equal to the welding tension between the conductor 15 and the conductive backplane 1, so as to ensure that the stresses between the conductor 15 and the battery cell 2 and between the conductor 15 and the conductive backplane 1 are balanced with each other, which can improve the bonding strength between the conductor 15 and the battery cell 2 and the conductive backplane 1, and enhance the mechanical strength and reliability of the photovoltaic module 100.

[0073] In some embodiments, the ratio of the length D3 of the third side 153 to the length D1 of the first side 151 satisfies 4 / 5≥D3 / D1≥1 / 2, for example 4:5, 4:6, 4:7, 1:2. Based on the above-mentioned size design, the conductor 15 serves as a conductor between the electrode 21 and the conductive backplane 1. The value of D3 affects the body resistance of the conductor 15, and also affects the welding pull-out force of the conductor 15. When D3 / D1 is less than 1 / 2, the body resistance of the conductor 15 is large, which is not conducive to the transmission of current. At the same time, the welding pull-out force is small, which is easy to cause the weld to fall off or break under the influence of external factors such as wind pressure and hail. When D3 / D1 is greater than 4 / 5, the conductor 15 tends to be a column, and is not tolerant to process errors. When the ratio of D3 / D1 is 1 / 2-4 / 5, the high conductivity of the conductor 15 is satisfied, the efficiency of the photovoltaic module 100 and the tolerance to process errors can be effectively improved, the reliability of welding between the conductor 15 and the battery cell 2 can be improved, and the risk of poor welding can be reduced.

[0074] In some embodiments, the ratio of the length D3 of the third side 153 to the length D2 of the second side 152 satisfies 7 / 10≥D3 / D2≥1 / 3, such as 7:10, 7:11, 7:12, 7:13, 1:2, 7:15, 7:16, 7:17, 7:18, 7:19, 7:20, 1:3. Based on the above-mentioned size design, the conductor 15 is a conductor between the battery cell 2 and the conductive backplane 1. The value of D3 affects the body resistance of the conductor 15 and also affects the welding pull-out force of the conductor 15. If D3 / D2 is less than 1 / 3, the body resistance of the conductor 15 is large, which is not conducive to the transmission of current. At the same time, the welding pull-out force is small, which is easy to cause the weld to fall off or break under the influence of external factors such as wind pressure and hail. If D3 / D2 is greater than 7 / 10, the conductor 15 tends to be a column and has no tolerance for process errors. When the ratio of D3 / D2 is 1 / 3-7 / 10, the high conductivity of the conductor 15 is met, which can effectively improve the efficiency of the photovoltaic module 100 and the fault tolerance to process errors, improve the reliability of welding between the conductor 15 and the conductive backplane 1, and reduce the risk of poor welding.

[0075] In some embodiments, the length of the first side 151 of the conductor 15 in contact with the electrode 21 is D1, which satisfies: 0.6 mm ≤ D1 ≤ 1 mm, for example 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm. When D1 is within the above range, the conductor 15 has a strong ability to collect the current on the electrode 21, the power of the photovoltaic module 100 is high, and the welding reliability between the conductor 15 and the electrode 21 is high, which can effectively reduce the risk of poor welding. When D1 is less than 0.6 mm, the contact resistance between the conductor 15 and the electrode 21 is large, which is not conducive to the conductor 15 collecting and transmitting the current on the electrode 21, and the welding pull-out force between the conductor 15 and the electrode 21 is small, which is easy to cause the weld to fall off or break when affected by external factors such as wind pressure and hail. When D1 is greater than 1 mm, the conductive performance and mechanical strength of the conductor 15 are redundant, resulting in a waste of conductive slurry.

[0076] In some embodiments, the length of the second side 152 of the conductor 15 in contact with the conductive layer 12 is D2, which satisfies: 0.7 mm ≤ D2 ≤ 1.1 mm; for example, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm and 1.1 mm. When D2 is within the above range, the high conductive efficiency of the conductor 15 and the reliability of welding between the conductor 15 and the conductive layer 12 are satisfied at the same time, reducing the risk of poor welding. When D2 is less than 0.7 mm, the contact resistance between the conductor 15 and the conductive layer 12 is large, which is not conducive to the current transmission between the conductor 15 and the conductive layer 12, and the welding pull-out force between the conductor 15 and the conductive layer 12 is small, which is easy to cause the weld to fall off or break when affected by external factors such as wind pressure and hail. When D2 is greater than 1.1 mm, the conductive performance and mechanical strength of the conductor 15 are redundant, resulting in a waste of conductive slurry.

[0077] In some embodiments, the length of the third side 153 at the narrowest point between the first side 151 and the second side 152 in the longitudinal section is D3, which satisfies: 0.5 mm ≤ D3 ≤ 0.9 mm, such as 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm and 0.9 mm. When D3 is within the above range, the amount of conductive paste such as solder paste or conductive glue is small, the cost is low, and there is a certain tolerance for process errors. When D is less than 0.5 mm, the body resistance of the conductor 15 is large, which is not conducive to the transmission of current. At the same time, the welding pull-out force is small, which is easy to cause the weld to fall off or break under the influence of external factors such as wind pressure and hail. When D3 is greater than 0.9 mm, the conductor 15 tends to be a column and is not tolerant to process errors.

[0078] In some embodiments, before the lamination process, the thickness of the insulating layer 11 is about 150 μm, corresponding to a height of 130 μm-160 μm of the conductor 15 in the photovoltaic module 100. The height of the conductor 15 varies with the thickness of the insulating layer 11, and the variation trend is consistent. The height of the conductor 15 is not limited in this application and can be designed according to actual needs.

[0079] In this application, the cross section of the conductor 15 refers to a plane figure obtained by cutting the conductor 15 parallel to the plane of the battery cell. In some embodiments, the cross section of the conductor 15 can be regular or irregular, the same or different, circular, elliptical, etc.

[0080] In some embodiments, in the cross-section of the conductor 15, the area of ​​the first cross-section through the first edge 151 is S1, the area of ​​the second cross-section through the second edge 152 is S2, and the area of ​​the third cross-section through the third edge 153 is S3, and: S1>S3, and / or S2>S3.

[0081] The larger the S1 is, the larger the contact area between the conductor 15 and the electrode 21 is, the smaller the contact resistance between the conductor 15 and the electrode 21 is, and the stronger the ability of the conductor 15 to collect the current on the electrode 21 is, thereby increasing the power of the photovoltaic module 100. On the other hand, the larger the contact area between the conductor 15 and the electrode 21 is, the greater the welding pull-out force between the conductor 15 and the electrode 21 is, which effectively prevents the photovoltaic module 100 from falling off or breaking at the welding point due to external factors such as wind pressure and hail during use. The smaller the S3 is, the smaller the area of ​​the third cross section through the third side 153 is, that is, the middle part of the conductor 15 is thinner, which can effectively reduce the amount of conductive paste such as solder paste or conductive glue, saving costs. In addition, such a design makes it possible for a gap to exist in the through hole 14 after the conductor 15 is filled into the through hole 14. In this way, in the process of preparing the photovoltaic module 100, even if there are errors introduced by the process such as the layout offset of the battery cell 2, the printing offset of the electrode 21, the offset of the conductor 15, the offset of the insulating layer 11, and the offset of the through hole 14 in the insulating layer 11 due to heat shrinkage or punching, resulting in the position mismatch between the electrode 21 and the through hole 14 in the insulating layer 11, it will not cause the conductor 15 in the through hole 14 to be unable to connect and conduct electricity. Therefore, the conductor 15 structure designed in this way can not only ensure the effective transmission of current, but also has a certain fault tolerance for the preparation process, so it can also correspondingly improve the yield of the photovoltaic module 100. In this application, S1>S3, the conductor 15 has a strong ability to collect current on the electrode 21, improves the power of the photovoltaic module 100, and the welding pull-out force between the conductor and the electrode 21 is large, and the reliability of the photovoltaic module 100 is high. Reduce the difficulty of the process, save the amount of conductive paste, and reduce costs.

[0082] The larger S2 is, on the one hand, the larger the contact area between the conductor 15 and the conductive layer 12, the smaller the contact resistance between the conductor 15 and the conductive layer 12, and the higher the current transmission efficiency, thereby increasing the power of the photovoltaic module 100. On the other hand, the larger the contact area between the conductor 15 and the conductive layer 12, the greater the welding pull-out force between the conductor 15 and the conductive layer 12, which effectively prevents the photovoltaic module 100 from falling off or breaking at the weld due to external factors such as wind pressure and hail during use. In the present application, S2>S3, the current transmission capacity between the conductor 15 and the conductive layer 12 is strong, the power of the photovoltaic module 100 is improved, the welding pull-out force between the conductor 15 and the conductive layer 12 is large, and the reliability of the photovoltaic module 100 is high. At the same time, the process difficulty is reduced, the amount of conductive paste used is saved, and the cost is reduced.

[0083] When S1>S3 and S2>S3, the ability of the conductor 15 to collect current on the electrode 21 is enhanced. At the same time, the current transmission ability between the conductor 15 and the conductive layer 12 is also significantly enhanced. Reducing S3 has little effect on the current collection and transmission efficiency of the conductor 15. While ensuring the current collection and transmission efficiency, the amount of conductive paste such as solder paste or conductive glue is greatly reduced, saving costs. In addition, such a design allows a gap to exist in the through hole 14 after the conductor 15 is filled into the through hole 14. In this way, during the preparation of the photovoltaic module 100, even if there are errors introduced by the process such as layout deviation of the battery cell 2, printing deviation of the electrode 21, deviation of the conductor 15, deviation of the insulating layer 11, deviation of the through hole 14 in the insulating layer 11 due to heat shrinkage or punching, resulting in the position mismatch between the electrode 21 and the through hole 14 in the insulating layer 11, it will not cause the conductor 15 in the through hole 14 to be unable to connect and conduct electricity. Therefore, the conductor 15 structure designed in this way can not only ensure the effective collection and transmission of current and reduce costs, but also has a certain fault tolerance for the manufacturing process and improves the yield of the photovoltaic module 100.

[0084] In the photovoltaic module 100, the electrode 21 on the cell 2 is generally made of precious metals with relatively high conductivity, such as silver, silver alloy, etc., so that the cell 2 has a higher current collection and transmission capability, thereby improving the efficiency of the photovoltaic module 100. However, due to cost considerations, the area of ​​the electrode 21 is generally small; the conductive layer 12 is used to cover the back of the entire photovoltaic module 100, and the amount is large. Therefore, due to cost considerations, relatively cheap materials such as copper foil, aluminum foil, or copper-aluminum composite foil are generally used, but their conductivity is relatively poor.

[0085] Therefore, in some embodiments, the conductor 15 is designed so that the ratio of the area S1 of its first cross-section to the area S2 of its second cross-section satisfies 1>S1 / S2≥1 / 2, for example 1:1.1, 1:1.2, 1:1.25, 1:1.3, 1:1.4, 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9, 1:2. The electrode 21 is made of a highly conductive material, such as silver, and the conductive layer 12 is made of a conductive material with relatively low conductivity, such as copper. Based on the above-mentioned 1>S1 / S2≥1 / 2 size design, the contact area between the conductor 15 and the conductive layer 12 is larger than the contact area between the conductor 15 and the electrode 21, which can increase the welding pull-out force between the conductor 15 and the conductive layer 12 and reduce the contact resistance between the conductor 15 and the conductive layer 12. The contact resistance between the conductor 15 and the conductive layer 12 can be basically the same as the contact resistance between the conductor 15 and the electrode 21, thereby improving the overall current collection and transmission efficiency of the conductor 15.

[0086] In some embodiments, the electrode 21 and the conductive layer 12 are made of materials with the same conductive properties, or the same conductive material, such as copper, S1 / S2=1. Based on the above-mentioned size design, the contact area between the conductor 15 and the conductive layer 12 is equal to the contact area between the conductor 15 and the electrode 21, and the welding pull-out force between the conductor 15 and the battery cell 2 is equal to the welding pull-out force between the conductor 15 and the conductive backplane 1, so as to ensure that the stresses between the conductor 15 and the battery cell 2 and between the conductor 15 and the conductive backplane 1 are balanced with each other, which can improve the bonding force between the conductor 15 and the battery cell 2 and the conductive backplane 1, and enhance the mechanical strength and reliability of the photovoltaic module 100.

[0087] In some embodiments, the ratio of the area S3 of the third cross section to the area S1 of the first cross section satisfies 4 / 5≥S3 / S1≥1 / 2, such as 4:5, 2:3, 4:7, 1:2. Based on the above-mentioned size design, the conductor 15 is a conductor between the battery cell 2 and the conductive backplane 1. The size of S3 affects the body resistance of the conductor 15, and also affects the welding pull-out force of the conductor 15. When S3 / S1 is less than 1 / 2, the body resistance of the conductor 15 is large, which is not conducive to the transmission of current. At the same time, the welding pull-out force is small, which is easy to cause the welding to fall off or break under the influence of external factors such as wind pressure and hail. When S3 / S1 is greater than 4 / 5, the conductor 15 tends to be a column and has no tolerance for process errors. When 4 / 5≥S3 / S1≥1 / 2, the high conductivity efficiency of the conductor 15 is satisfied at the same time, which can effectively improve the efficiency of the photovoltaic module 100 and the tolerance for process errors, improve the reliability of welding between the conductor 15 and the battery cell 2, and reduce the risk of poor welding.

[0088] In some embodiments, the ratio of the area S3 of the third cross section to the area S2 of the second cross section satisfies 9 / 10≥S3 / S2≥1 / 3, for example, 9:10, 9:11, 9:12, 9:13, 2:3, 9:14, 9:15, 9:16, 9:17, 9:18, 9:19, 9:20, 9:21, 9:22, 9:23, 9:24, 9:25, 9:26, 1:3. In some embodiments, the ratio of the area S3 of the third cross section to the area S2 of the second cross section satisfies 9 / 10≥S3 / S2≥1 / 3. Based on the above-mentioned size design, the conductor 15 acts as a conductor between the battery cell 2 and the conductive backplane 1, and the size of S3 affects the body resistance of the conductor 15, and also affects the welding pull-out force of the conductor 15. When S3 / S2 is less than 1 / 3, the body resistance of the conductor 15 is large, which is not conducive to the transmission of current. At the same time, the welding pull-out force is small, which can easily cause the weld to fall off or break under the influence of external factors such as wind pressure and hail. When S3 / S2 is greater than 9 / 10, the conductor 15 tends to be cylindrical and has no tolerance for process errors. When 9 / 10≥S3 / S2≥1 / 3, the high conductivity efficiency of the conductor 15 is met at the same time, which can effectively improve the efficiency of the photovoltaic module 100 and the tolerance for process errors, improve the reliability of welding between the conductor 15 and the conductive backplane 1, and reduce the risk of poor welding.

[0089] In some embodiments, the area of ​​the first cross section of the conductor 15 in contact with the electrode 21 is S1, which satisfies: 0.36 mm²≤S1≤1 mm², for example, 0.36 mm², 0.4 mm², 0.5 mm², 0.6 mm², 0.7 mm², 0.8 mm², 0.9 mm², 1 mm². When S1 is within the above range, the conductor 15 has a strong ability to collect the current on the electrode 21, and the power of the photovoltaic module 100 is high. At the same time, the welding reliability between the conductor 15 and the electrode 21 is high, which can effectively reduce the risk of poor welding. When S1 is less than 0.36 mm², the contact area is small, and the contact resistance between the conductor 15 and the electrode 21 is large, which is not conducive to the conductor 15 collecting and transmitting the current on the electrode 21, and the welding pull-out force between the conductor 15 and the electrode 21 is small, which is easy to cause the weld to fall off or break when affected by external factors such as wind pressure and hail. When S1 is greater than 1 mm², the conductive performance and mechanical strength of the conductor 15 are redundant, resulting in a waste of the conductive paste.

[0090] In some embodiments, the area of ​​the second cross section of the conductor 15 in contact with the conductive layer 12 is S2, which satisfies: 0.49 mm²≤S2≤1.21 mm², such as 0.49 mm², 0.6 mm², 0.7 mm², 0.8 mm², 0.9 mm², 1 mm², 1.1 mm² and 1.21 mm². When S2 is within the above range, the high conductivity efficiency of the conductor 15 and the reliability of the welding between the conductor 15 and the conductive layer 12 can be met, and the risk of poor welding can be reduced. When S2 is less than 0.49 mm², the contact resistance between the conductor 15 and the conductive layer 12 is large, which is not conducive to the current transmission between the conductor 15 and the conductive layer 12, and the welding pull-out force between the conductor 15 and the conductive layer 12 is small, which is easy to cause the weld to fall off or break when affected by external factors such as wind pressure and hail. When S2 is greater than 1.21 mm², the conductive performance and mechanical strength of the conductor 15 are redundant, resulting in a waste of conductive slurry.

[0091] In some embodiments, the area of ​​the third cross section located between the first cross section and the second cross section and corresponding to the narrowest part in the longitudinal section of the conductor 15 is S3, which satisfies: 0.25 mm²≤S3≤0.81 mm². For example, 0.25 mm², 0.3 mm², 0.4 mm², 0.5 mm², 0.6 mm², 0.7 mm², and 0.81 mm². When S3 is within the above range, the amount of conductive paste such as solder paste or conductive glue is small, the cost is low, and there is a certain tolerance for process errors. When S is less than 0.25 mm², the body resistance of the conductor 15 is large, which is not conducive to the transmission of current. At the same time, the welding pull-out force is small, which is easy to cause the weld to fall off or break under the influence of external factors such as wind pressure and hail. When S3 is greater than 0.81 mm², the conductor 15 tends to be a column and is not tolerant to process errors.

[0092] Figure 6 A partial schematic diagram of a battery cell 2 is shown in which the electrode 21 is a PAD point 212 according to some embodiments of the present application.

[0093] When the electrode 21 of the battery cell 2 is the PAD point 212, in the longitudinal section of the conductor 15, the length D1' of the first side 151 of the conductor 15 in contact with the PAD point 212 and the width D of the PAD point 212 in the direction of the first side 151 satisfy 3 / 4≤D1' / D≤1, for example 1:1, 3:3.1, 3:3.2, 3:3.3, 3:3.4, 3:3.5, 3:3.6, 3:3.7, 3:3.8, 3:3.9, 3:4. In the conductor 15, if D1' / D>1, the conductor 15 will cover the outside of the PAD point 212, which will cause a short circuit in the photovoltaic module 100; if D1' / D<3 / 4, it will not be possible to ensure that there is sufficient welding pull-out force between the conductor 15 and the PAD point 212, which may cause risks such as cold soldering or poor welding; by controlling D1' / D within the above range, while ensuring the welding pull-out force between the conductor 15 and the PAD point 212, the occurrence of a short circuit can also be avoided.

[0094] In some embodiments, the length D1' of the first side 151 of the conductor 15 in contact with the PAD point 212, the length D2 of the second side 152 of the conductor 15 in contact with the conductive layer 12, and the width D of the PAD point 212 in the direction of the first side 151 satisfy |D1'-D2| / D < 0.1. In the conductor 15, the above ratio is controlled to be less than 0.1, that is, the ratio is small, and the above range can be satisfied when the values ​​of D1' and D2 are equal or relatively close. Such a design makes the bonding force between the conductor 15 and the PAD point 212 and the conductive layer 12 equal or similar, which can improve the bonding force between the conductor 15 and the PAD point 212 and the conductive layer 12, thereby improving the mechanical strength and reliability of the photovoltaic module 100.

[0095] In some embodiments, the area S1' of the first cross section of the conductor 15 at the contact with the PAD point 212 and the area S of the cross section of the PAD point 212 at the contact with the conductor 15 satisfy 3 / 4≤S1' / S≤1, for example, 3:4, 3.1:4, 3.2:4, 3.3:4, 3.4:4, 3.5:4, 3.6:4, 3.7:4, 3.8:4, 3.9:4, 1:1. In the conductor 15, if S1' / S>1, the conductor 15 will cover outside the PAD point 212, which will cause a short circuit in the photovoltaic module 100; if S1' / S<3 / 4, it will not be possible to ensure that there is enough welding area between the conductor 15 and the PAD point 212, which may cause risks such as cold welding or poor welding. In addition, if the welding area between the conductor 15 and the PAD point 212 is too small, the PAD point 212 will not be fully utilized, resulting in a waste of metal such as silver; controlling S1' / S within the above range can not only ensure sufficient welding between the conductor 15 and the PAD point 212, and full utilization of the PAD point 212, but also avoid the occurrence of short circuits.

[0096] In some embodiments, the area S1' of the first cross section where the conductor 15 contacts the PAD point 212, the area S2 of the second cross section through the second side 152, and the area S of the cross section where the PAD point 212 contacts the conductor 15 satisfy |S1'-S2| / S < 0.1. It can be understood that the difference of |S1'-S2| represents the absolute value of the difference between the contact area between the conductor 15 and the PAD point 212 and the contact area between the conductor 15 and the conductive layer 12, and |S1'-S2| / S represents the ratio of the absolute value of the above contact area difference to the area of ​​the PAD point 212. In the conductor 15, the above ratio is controlled to be less than 0.1, which can be understood as the contact area between the conductor 15 and the PAD point 212 is equal to or close to the contact area between the conductor 15 and the conductive layer 12. Such a design makes the bonding force between the conductor 15 and the PAD point 212 and the conductive layer 12 the same or close, which can improve the bonding force between the conductor 15 and the PAD point 212 and the conductive layer 12, thereby improving the mechanical strength and reliability of the photovoltaic module 100.

[0097] In some embodiments, the thickness of the intermetallic compound layer at the interface between the conductor 15 and the electrode 21 is 0.5-3 μm, such as 0.5 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, and / or the thickness of the intermetallic compound layer at the interface between the conductor 15 and the conductive layer 12 is 0.5-3 μm, such as 0.5 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm. The thickness of the intermetallic compound layer is controlled within the above range, and such a structure can provide a larger tensile strength, thereby improving the welding quality.

[0098] In some embodiments, the first cross section may be a cross section of an intermetallic compound layer at an interface between conductor 15 and electrode 21 , and the second cross section may be a cross section of an intermetallic compound layer at an interface between conductor 15 and conductive layer 12 .

[0099] In the present application, in the longitudinal section of the conductor 15, the bottom angle 154 is the angle between the tangent of the side in the plane figure of the longitudinal section and the first side 151. In some embodiments, the bottom angle 154 is 30°-85°, for example, 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65°, 70°, 75°, 80°, 85°. The size of the bottom angle 154 reflects the change gradient of the cross-sectional area of ​​the conductor 15. The larger the bottom angle 154, the better the tensile strength. However, when the bottom angle 154 is greater than 85°, the amount of conductor used is large, but the current transmission efficiency is improved less, and the process fault tolerance is sacrificed, and the input-output ratio is small. When the bottom angle 154 is less than 30°, the change gradient of the cross-sectional area of ​​the conductor 15 is large, the tensile strength is poor, and the product reliability requirements cannot be met.

[0100] Optionally, the bottom angle 154 is 60°-70°. If the bottom angle 154 is controlled within the above range, the gradient of the cross-sectional area of ​​the conductor 15 is more moderate, the tensile strength and welding pull-out force of the conductor 15 are better, and the conductive performance is also better.

[0101] In addition, such a design allows a gap to be left in the through hole 14 after the conductor 15 is filled. Thus, even in the process of preparing the photovoltaic module 100, even if there are errors introduced by the process such as the layout deviation of the cell 2, the printing deviation of the electrode 21, the deviation of the conductor 15, the deviation of the insulating layer 11, the deviation of the through hole 14 in the insulating layer 11 due to heat shrinkage or punching, etc., resulting in the position mismatch between the electrode 21 and the through hole 14 in the insulating layer 11, it will not cause the conductor 15 in the through hole 14 to be unable to connect and conduct electricity. Therefore, the conductor 15 structure designed in this way can not only ensure the effective collection of current, but also has a certain fault tolerance for the preparation process, so it can also correspondingly improve the yield of the photovoltaic module 100.

[0102] Continue to refer Figure 1 The conductor 15 is disposed in the through hole 14 in the insulating layer 11, and is used to electrically interconnect the electrode 21 on the battery body 22 with the conductive layer 12 in the conductive back plate 1, and the conductor 15 is a columnar structure.

[0103] As understood by those skilled in the art, a "column" is a shape in which two faces are parallel and identical to each other, and can be divided into cylinders and prisms. In a cylinder, there are two faces that are parallel and identical to each other, and the intersection lines of each of the remaining two adjacent faces are parallel to each other. Among them, the two faces that are parallel and identical to each other can be respectively called "upper base surface" and "lower base surface", and the surface connecting the upper base surface and the lower base surface is called the side surface. In this application, "quasi-column" refers to two faces that are parallel to each other but have the same or similar shapes. Therefore, if the columnar structure is considered to be a structure in which the upper base surface and the lower base surface are consistent, then the quasi-column structure in this application is a structure in which the upper base surface and the lower base surface are not completely identical. Therefore, it can be understood that, Figure 1 Only one case of the columnar structure of the conductor 15 is shown, and the conductor 15 may also have other structures.

[0104] It can be understood that the conductor 15 is formed by curing a conductive paste such as solder paste or conductive glue. Therefore, by controlling the parameters of the preparation process of the conductor 15, such as upper and lower lamination temperatures, temperature gradient, pressure, pressure gradient, lamination time, etc., and by selecting the material for preparing the conductor 15, such as a material with a specific melting point and a certain wettability on the electrode 21 and the conductive layer 12, a conductor 15 with different morphologies can be obtained.

[0105] In some embodiments of the present application, a conductor 15 is disposed in a through hole 14 on the insulating layer 11, and the conductor 15 is designed to be a columnar structure, so that when it is placed in the through hole 14 in the insulating layer 11, only the upper bottom surface, the lower bottom surface, or the upper bottom surface and the lower bottom surface of the conductor 15 completely fill the through hole 14, and the other parts do not completely fill the through hole 14, that is, there is a gap in the through hole 14, so that even if the electrode 21 and the through hole 14 in the insulating layer 11 are offset in the process of preparing the photovoltaic module 100, it will not cause the conductor 15 in the through hole 14 to be unable to connect and conduct electricity. Therefore, the conductor 15 structure designed in this way can not only ensure the effective collection of current, but also has a certain fault tolerance for the preparation process, so it can also correspondingly improve the yield of the photovoltaic module 100.

[0106] In some embodiments, the conductor 15 is a cylindrical structure, wherein the upper bottom surface and the lower bottom surface are both circular. The corresponding battery cell 2 may be a multiple-busbar (MBB) battery cell 2 .

[0107] In some embodiments, the conductor 15 is an elliptical column structure, wherein the upper bottom surface and the lower bottom surface are both elliptical. The corresponding battery cell 2 can be a 0-Busbar (abbreviated as 0BB) battery cell 2.

[0108] In some embodiments, the electrode 21 is a PAD point 212, and the PAD point 212 is electrically interconnected with the conductive layer 12 through the conductor 15, wherein the orthographic projection shape of the PAD point 212 on the battery body 22 is a circle, a chamfered square, or a chamfered rectangle.

[0109] In some embodiments, when the orthographic projection shape of the PAD point 212 on the battery body 22 is a circle, a conductor 15 with a cylindrical structure that fits the circular shape can be set for electrical interconnection; when the orthographic projection shape of the PAD point 212 on the battery body 22 is a square with chamfers, a conductor 15 with a cylindrical structure that fits the square shape can be set for electrical interconnection; when the orthographic projection shape of the PAD point 212 on the battery body 22 is a rectangle with chamfers, two or more conductors 15 with cylindrical structures can be set for electrical interconnection, or one or more conductors 15 with elliptical column structures can be set for electrical interconnection.

[0110] In some embodiments, the battery sheet 2 has a first PAD point 212 and a second PAD point 212 , wherein an area of ​​an orthographic projection of the first PAD point 212 on the battery body 22 is greater than an area of ​​an orthographic projection of the second PAD point 212 on the battery body 22 .

[0111] In the existing design, the first PAD point 212 and the second PAD point 212 have the same number of conductors 15. Usually, more conductive paste is printed on the first PAD point 212, and less conductive paste is printed on the second PAD point 212. This will cause the height of the conductive paste on the first PAD point 212 to be greater than the height of the conductive paste on the second PAD point 212, thereby causing inconsistent welding heights and poor welding. In some embodiments, the number of conductors 15 in contact with the first PAD point 212 is greater than the number of conductors 15 in contact with the second PAD point 212. In this technical solution, by setting a larger number of conductors on the first PAD point, the height of the conductive paste in contact with the first PAD point can be reduced, ensuring the consistency of the welding height and the welding yield of the photovoltaic module 100, thereby avoiding the problem of low welding yield due to inconsistent welding height in the prior art. For the specific number of conductors 15, those skilled in the art can select as needed, as long as it is guaranteed that the technical effect produced by the above-mentioned conductors 15 can be achieved.

[0112] In some embodiments, the material of the conductor 15 is a tin-bismuth alloy, such as a tin-bismuth alloy, a tin-lead-bismuth alloy, a tin-bismuth-copper alloy, or a tin-bismuth-silver alloy.

Claims

1. A photovoltaic module, characterized in that: The photovoltaic module includes a battery cell, a conductor and a conductive backplane. The battery cell includes a battery body and an electrode disposed on the battery body; The conductive backplane comprises an insulating layer, a conductive layer and a back adhesive film stacked in sequence, wherein the insulating layer has a plurality of through holes penetrating the insulating layer; The conductor is arranged in the through hole, and the electrode on the battery body is electrically interconnected with the conductive layer through the conductor. In the longitudinal section of the conductor, the length of the first side of the conductor in contact with the electrode is D1, the length of the second side of the conductor in contact with the conductive layer is D2, the first side and the second side are arranged on opposite sides of the conductor, and the length of the third side located at the narrowest point between the first side and the second side in the longitudinal section is D3, and: D1>D3, and / or D2>D3.

2. The photovoltaic module according to claim 1, characterized in that: A ratio of the length D1 of the first side to the length D2 of the second side is 1≥D1 / D2≥1 / 2.

3. The photovoltaic module according to claim 1, characterized in that: The ratio of the length D3 of the third side to the length D1 of the first side is 4 / 5≥D3 / D1≥1 / 2.

4. The photovoltaic module according to claim 1, characterized in that: The ratio of the length D3 of the third side to the length D2 of the second side is 7 / 10≥D3 / D2≥1 / 3.

5. The photovoltaic module according to claim 1, characterized in that: The length of the first side is D1, satisfying: 0.6mm≤D1≤1mm; and / or the length of the second side is D2, satisfying: 0.7mm≤D2≤1.1mm; and / or the length of the third side is D3, satisfying: 0.5mm≤D3≤0.9mm.

6. The photovoltaic module according to claim 1, characterized in that: In the cross section of the conductor, the area of ​​the first cross section passing through the first side is S1, the area of ​​the second cross section passing through the second side is S2, and the area of ​​the third cross section passing through the third side is S3, and: S1>S3, and / or S2>S3.

7. The photovoltaic module according to claim 6, characterized in that: The ratio of the area S1 of the first cross section to the area S2 of the second cross section is 1≥S1 / S2≥1 / 2.

8. The photovoltaic module according to claim 6, characterized in that: The ratio of the area S3 of the third cross section to the area S1 of the first cross section is 4 / 5≥S3 / S1≥1 / 2.

9. The photovoltaic module according to claim 6, characterized in that: The ratio of the area S3 of the third cross section to the area S2 of the second cross section is 9 / 10≥S3 / S2≥1 / 3.

10. A photovoltaic module, characterized in that: The photovoltaic module includes a battery cell, a conductor and a conductive backplane. The battery cell includes a battery body and an electrode disposed on the battery body; The conductive backplane comprises an insulating layer, a conductive layer and a back adhesive film stacked in sequence, wherein the insulating layer has a plurality of through holes penetrating the insulating layer; The conductor is arranged in the through hole, and the electrode on the battery body is electrically interconnected with the conductive layer through the conductor. In the cross section of the conductor, the area of ​​the first cross section where the conductor contacts the electrode is S1, and the area of ​​the second cross section where the conductor contacts the conductive layer is S2. The first cross section and the second cross section are arranged on opposite sides of the conductor, and the area of ​​the third cross section between the first cross section and the second cross section corresponding to the narrowest point in the longitudinal section of the conductor is S3, and: S1>S3, and / or S2>S3.

11. The photovoltaic module according to claim 10, characterized in that: The ratio of the area S1 of the first cross section to the area S2 of the second cross section is 1≥S1 / S2≥4 / 5.

12. The photovoltaic module according to claim 10, characterized in that: The ratio of the area S3 of the third cross section to the area S1 of the first cross section is 4 / 5≥S3 / S1≥2 / 3.

13. The photovoltaic module according to claim 10, characterized in that: The ratio of the area S3 of the third cross section to the area S2 of the second cross section is 9 / 10≥S3 / S2≥2 / 3.

14. The photovoltaic module according to claim 10, characterized in that: The area of ​​the first cross section is S1, satisfying: 0.36mm²≤S1≤1mm²; and / or the area of ​​the second cross section is S2, satisfying: 0.49mm²≤S2≤1.21mm²; and / or the area of ​​the third cross section is S3, satisfying: 0.25mm²≤S3≤0.81mm².

15. The photovoltaic module according to claim 1 or 10, characterized in that: The electrode is a main grid line, a thin grid line, or a combination of one or more of a grid line thickening segment.

16. The photovoltaic module according to claim 1 or 10, characterized in that: The electrodes are PAD points.

17. The photovoltaic module according to claim 16, characterized in that: In the longitudinal section of the conductor, the length of the first side of the conductor in contact with the PAD point is D1', the width of the PAD point in the direction of the first side is D, and 3 / 4≤D1' / D≤1.

18. The photovoltaic module according to claim 17, characterized in that: In the longitudinal section of the conductor, the length of the second side of the conductor in contact with the conductive layer is D2, |D1'-D2| / D < 0.

1.

19. The photovoltaic module according to claim 16, characterized in that: The area of ​​the first cross section of the conductor at the point of contact with the PAD is S1', and the area of ​​the cross section of the PAD point at the point of contact with the conductor is S, 3 / 4≤S1' / S≤1.

20. The photovoltaic module according to claim 19, characterized in that: │S1'-S2│ / S < 0.

1.

21. The photovoltaic module according to claim 1 or 10, characterized in that: The thickness of the intermetallic compound layer at the interface between the conductor and the electrode is 0.5-3 μm, and / or the thickness of the intermetallic compound layer at the interface between the conductor and the conductive layer is 0.5-3 μm.

22. The photovoltaic module according to claim 1 or 10, characterized in that: In the longitudinal section of the conductor, the base angle is 30°-85°.

23. The photovoltaic module according to claim 22, characterized in that: In the longitudinal section of the conductor, the base angle is 60°-70°.

24. The photovoltaic module according to claim 1 or 10, characterized in that: The conductor is a column-like structure.

25. The photovoltaic module according to claim 24, characterized in that: The columnar-like structure includes: a cylindrical-like structure and an elliptical-column-like structure.

26. The photovoltaic module according to claim 24, characterized in that: The electrode is a PAD point, and the PAD point is electrically interconnected with the conductive layer through the conductor, wherein the orthographic projection shape of the PAD point on the battery body is a circle, a chamfered square, or a chamfered rectangle.

27. The photovoltaic module according to claim 26, characterized in that: The battery sheet has a first PAD point and a second PAD point, wherein an area of ​​an orthographic projection of the first PAD point on the battery body is larger than an area of ​​an orthographic projection of the second PAD point on the battery body.

28. The photovoltaic module according to claim 27, characterized in that: The number of the conductors in point contact with the first PAD is greater than the number of the conductors in point contact with the second PAD.

29. The photovoltaic module according to claim 1 or 10, characterized in that: The material of the conductor is an alloy containing tin and bismuth.

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